Speed converting mechanism

ABSTRACT

A MECHANSIM FOR SELECTIVELY CONVERTING A CONSTANT VELOCITY, CONSTANT THROW MOVEMENT OF A TAPE INTO A ROTARY OSCILLATION OF AN OBJECT SCANNING MIRROR AT A PRESELECTED CONSTANT VELOCITY.

D. W. 'TATES SPEED CONVERTING MECHANISM 6 Sheets-Sheet l giaju n 45. 1968 INVENTOR.

' DONALD W. TATES BYW y.

[ ATTORNEYS Jan. 5, 1971 D. w. TATES 3,552,221

} v SPEED CONVERTING MECHANISM Filed April 15, 1968 e Sheets-Sheet a."F/ 6 2 I INVENTQR.

DONAL D W. TATES BY W4 ,y.

ATTOR/VE rs Jan. 5, 1971 o.w. 1'A'rl-:s

I SPEED CONVERTING MECHANISM GSheets-Sheet 5 Filed April15 1968 FIG. 4

R m .4 OT 8 TA. Y NT E m w m N 0 1D T L T M .A O D 1971 D. w. TATES 1'SPEED CONVERTING MECHANISM 6 Sheets-Sheet 4 Filed Ap ril 15. 1968INVENTOR. DONALD w. TATES WQL BY u-Q ATTORNEYS Jan. 5, 1971; D. w.TATES- SPEED CONVERTING MECHANISM 6 Sheets-Sheet 5 Filed A ril 15, 1968INVENTOR. DONALD w. TATES ATTORNEYS Jan. 5,197] I n. w. TATES SPEEDCONVERTING MECHANISM Filed April [15. 1968 6 Sheets-Sheet 6 0 ws m TT ENA N E W WW /7 I 7 L M A A W L Y 7 B United States Patent US. 01. 74-1426 Claims ABSTRACT OF THE DISCLOSURE A mechanism for selectively.converting a constant velocity, constant throw movement of a tape into arotary oscillation of an object scanning mirror at a preselectedconstant velocity.

This invention relates to a mechanism for converting a constant velocityconstant throw movement into a rotary oscillation at a preselectedconstant velocity. More particularly, this invention relates to amechanism for rotationally oscillating an object scanning mirror at anyone of a plurality of preselected constant velocities from a constantvelocity, constant throw motion-imparting tape.

In the practice of xerography, as described in US. Pat. No. 2,297,691 toChester F. Carlson, a xerographic surface comprising a layer ofphotoconductive insulating material aflixed to a conductive backing isused to support electrostatic images. In the usual method of carryingout the process, the xerographic surface is electrostatically chargeduniformly over its surface and then exposed to a light pattern of theimage being reproduced to thereby discharge the charge in the areaswhere light strikes the layer. The undischarged areas of the layer thusform an electrostatic charge pattern in conformity with theconfiguration of the original light pattern. I

The latent electrostatic image can then be developed by contacting itwith a finely divided electrostatically attractable material such as apowder. The powder is held in image areas by the electrostatic chargeson the layer. Where the charge field is greatest, the greatest amount ofmaterial is deposited; where the charge field is least, little or nomaterial is deposited. Thus a powder image is produced in conformitywith the light image of copy being reproduced. The powder issubsequently transferred to a sheet of paper or other surface andsuitably affixed thereto to form a permanent print.

Most xerographic equipment in commercial use today is adapted to createcopies of originals at about a 1:1 optical rate. That is to say, itreproduces the original in size as well as content.

Various approaches have been proposed to provide automatic andcontinuous xerographic reproducing machines with the capability ofcreating copy at any one of a plurality of optical reductions. One suchapproach is described in copending application Ser. No. 682,830 filedNov. 14, 1967 in the name of Robert Schaeffer. According to thatdisclosure, optical reductions are achieved by varying the lens positionand characteristics, as through an additional lens, while retaining afixed conjugate length. In another copending application, applicationSer. No. 721,321 filed concurrently herewith, in .the names of LawrenceA. Ferguson, Robert K. Jones, and Donald W. Tates, another approach tothis problem is described. According to that disclosure, variableoptical reductions are attained by varying the conjugate length of theimaging system while appropriately repositioning the lens along theoptical path. In either approach, however, it is necessary to vary therate of optical scan as a function of the imaging path characteristicsso that an undistorted reproduction of the original may be retained.

3,552,221 Patented Jan. 5, 1971 The present invention is directed to amechanism for permitting the optical scanning of an object by an objectscanning mirror at any one of a plurality of preselected scan rates. Themechanism operates from an input in the form of a constant velocityconstant throw tape generally of the type described in either of theaforementioned pending patent applications. Its output is in the form ofa rotational oscillation of the object scanning mirror. The mechanism,however, has the ability to move the mirror from a fixed start-of-scanposition regardless of the rotational velocity desired. And each of thepreselected velocities results in a constant speed of rotation duringscanning.

I It is therefore an object of the instant invention to optically scanan object to be reproduced.

Another object of the instant invention is to scan an object to bereproduced at any one of a plurality of preselected speeds of rotation.

A further object of the instant invention is to convert a constantvelocity constant throw mechanical input into any one of a plurality ofconstant velocity outputs.

A further object of the instant invention is to rotationally oscillatean object scanning mirror at a preselected speed through a mechanismhaving an input in the form of a constant velocity constant throw.

A further object of the invention is to oscillate an object scanningmirror at any one of a plurality of scan rates from a single,preselected, start-of-scan position.

Another object of the instant invention is to vary the scan rate of avariable optical image projector through the use of a cam followercooperable with a multi-lobe cam, the employed cam lobe dictating thescan rate and consequently the optical reduction.

These and other objects of the instant invention are attained inaccordance with the present invention by a novel mechanical assembly forconverting the constant velocity linear reciprocation of a tape intoaconstant velocity reciprocatory oscillation of a shaft which maysupportan object scanning mirror of a xerographic reproducing machine.Operatively interconnecting the tape and shaft are mechanical elementswhich are indexable so that the velocity of the oscillating mirrorsupporting the shaft is Variable while the reciprocatory velocity of thetape is fixed. When employed in a xerographic reproducing machine,theindexing of the mechanism may be correlated with the opticalmagnification of the imaging system for creating developable latentelectrostatic images which have proportionate lengths and widths. Theillustrative mechanism of the instant invention includes a reciprocabletape movable to oscillate a drive member about a shaft on which anobject scanning mirror oscillates. A drive segment is pivotally mountedon the drive member while a driven segment is mounted for oscillationabout the shaft for oscillating the scanning mirror. The driven segmentis moved by the drive segment through elements which may be in the formof meshing gear teeth. The drive segment is also provided with a camfollower which is offset from the axis of rotation of the shaft as wellas offset from the axis of rotation of the drive segment Within thedrive member. The cam follower is coactable with one of a plurality ofindexable cam faces. Movement of the drive member will thus move theaxis of rotation of the drive segment to rotate it. The supplementalmovement of the cam follower along one of the cam faces will addrotational movement to the drive segment so that the driven segment andscanning mirror are oscillated as a function of the particular cam faceindexed into contact with the cam follower portion of the drive segment.

Further objects of this invention, together with additional features andadvantages thereof, will become apparent from the following descriptionof one embodiment of the invention when read in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a schematic representation of an automatic xerographicreproducing machine utilizing the invention of the application;

FIG. 2 is a perspective view of the optical system of the invention andthe drive system for the various cooperative elements associated withthe xerographic drum;

FIG. 3 is a perspective view of the lens and lens moving elements;

FIG. 4 is a side view of the lens and lens moving elements;

FIG. 5 is a top plan view of the elements shown in FIG. 3;

FIG. 6 is a perspective view of the image mirror and image mirror movingelements;

FIG. 7 is a top view of the image mirror and image mirror movingelements;

FIG. 8 is a side view of the elements shown in FIG. 6 with parts brokenaway for clarity;

FIG. 9 is a perspective view of the object mirror and motion impartingelements;

FIG. 10 is a top plan view of part of the object mirror and motionimparting elements; and

FIG. 11 is a sectional view of the motion imparting elements taken alongline 1111 of FIG. 10.

Referring now to the drawings, there is shown in FIG. 1 an embodiment ofthe subject invention in a suitable environment such as an automaticxerographic reproducing machine. The automatic xerographic reproducingmachine includes a xerographic plate or surface 10 formed in the shapeof a drum. The plate has a photoconductive layer or light receivingsurface on a conductive backing, journaled in a frame to rotate in thedirection indicated by the arrow. The rotation will cause the platesurface to sequentially pass a series of xerographic processingstations. For the purposes of the present disclosure, the severalxerographic processing stations in the path of movement of the platesurface may be described functionally, as follows: I

A charging station A, at which a uniform electrostatic charge isdeposited on the photoconductive plate;

An exposure station B, at which light or radiation pattern of copy to bereproduced is projected onto the plate surface to dissipate the chargein the exposed areas thereof to thereby form a latent electrostaticimage of the copy to be reproduced;

A developing station C at which xerographic developing material,including toner particles having an electrostatic charge opposite tothat of the latent electrostatic image, is cascaded over the platesurface whereby the toner particles adhere to the latent electrostaticimage to form a toner-powder image in a configuration of the copy beingreproduced;

A transfer station D at which the tone-powder image is electrostaticallytransferred from the plate surface to a transfer material or a supportsurface; and,

A drum cleaning and discharge station E at which the plate surface isbrushed to remove residual toner partices remaining thereon after imagetransfer and exposed to a relatively bright light source to effectsubstantially complete discharge of any residual electrostatic chargeremaining thereon.

It is felt that the preceding description of the xerographic process issuflicient for an understanding of the invention. Further details may behad by reference to U.S. Pat. No. 3,301,126 issued to Osborne et al.

Referring again toFIG. 1, a xerographic drum is rotated and anincremental area of a document on a platen 12 is scanned at a rate suchthat the optical image is stationary relative to the xerographic drum.The optical scanning or projection system disclosed herein projects aflowing image onto the surface of the photoconductive drum from astationary original. The optical scanning or projection assemblycomprises a stationary copy board which includes a transparent curvedplaten member 12, such as, for example, a glass plate or the likepositioned on the exterior of the machine and adapted to support adocument to be reproduced. The document is uniformly illuminated andarranged in light projection relation to the moving light-receivingsurface of the xerographic drum. Uniform lighting is provided by banksor lamps LMPS arranged on opposite sides of the platen.

Scanning of the document on the stationary platen is accomplished bymeans of an object mirror assembly 14 which is oscillated relative tothe platen in timed relation to the movement of the xerographic drum.The mirror assembly, which includes an object mirror 16, is mountedbelow the copy holder to reflect an image of the document past a lensassembly 18 including a lens 20, to an image mirror assembly 22including an image mirror 24 which, in turn, reflects the image onto thexerographic drum through a slot in the fixed light shield 26 positionedadjacent to the xerographic drum surface. In the embodiment of theinvention shown, the scanning of images such as original documents isaccomplished by placing the original copy on the copy holder 12 andscanning. the document by means of oscillating the object mirror 16,through a lens 20 onto a image mirror 24 which, in turn, reflects theimage through a slotted light shield 26 onto the xerographic drum 10.

The exposure mechanism includes an optical frame 28 for supporting theobject mirror, lens and image mirror. The optical frame 28 is supportedbetween the machine frames, one of which, .30, is partially shown inFIG. 2.

The platen 12, made of transparent material such as glass, is suitablysupported by the lamp holder frame assembly directly over the axis ofrotation of the object mirror 16. Platen 12 is curved in the shape of anarc, with the radius thereof equal to the distance from the platensurface to the axis of rotation of the object mirror 16.

The original document to be reproduced is placed on the curved platen12. Uniform illumination is achieved by banks of lights such asfluorescent lamps LMPS mounted in conventional fluorescent lamp holdersecured to a suitable lamp holder frame assembly.

Object mirror 16 is supported by a suitable mirror support assemblyfixed to a mirror shaft 32 journaled by suitable bearings mounted inoptical frame 28. It is noted that this assembly positions the objectmirror in a flattened portion of the shaft 32 so that the reflectingsurface of the mirror is in a plane extending through the axis of shaft32.

Oscillating of shaft 32 and therefore the scanning or object mirror 16is governed by a controller hereinafter described in detail. Motion inone direction, during scaning, is generally effected by means of drivesystem 34 comprising a steel tape 36 secured at one end to a portion ofthe controlled segment 38 and at the other end to controller segment 40which is driven in synchronization with the rotation of the xerographicdrum. Motion is imparted to controller segment 40 through shaft 42,follower arm 44, cam follower 46, driven cam 48 and motor 50. The mirroris then returned to its start-of-scan position by means of a spring 52connected at one end to a pin 54 fixed to the controller and at itsother end to a pin 56 secured in the optical frame 28 to normally biasthe mirror into the start-of-scan position. These elements are the sameas disclosed in the aforementioned Osborne et al. patent so furtherdescriptions herein are not deemed necessary. The differences betweenthe object mirror scanning elements of the instant system and that ofOsborne et al. reside between the controlled segment 38 and shaft 32, adetailed description of which appears hereinafter.

As shown in FIGS. 1, 3, 4, and 5, lens 20 is mounted between the objectmirror 16 and image mirror 24 in an image projecting relationshiptherewith. The lens is optical system.

mounted in a shiftable lens block or carriage 58 for movement along theoptical axis of the imaging system. The carriage 58 includes a pair ofapertures '60 to effect sliding movement of the carriage on fixed guiderods 62. The guide rods 62 are held fixed with respect to the machineframe by means of bolts 64 at opposite ends of the guide rods whichfixedly mount the rods on machine frame extensions 66.

Rotatably mounted atopposite ends in the machine frame extensions 66 isa rotatable lens carriage jack screw 68 having a threaded surface inmating engagement with threaded aperture 70 in lens carriage 58.Rotation is imparted to the jack screw through driven pulley 72 anddrive pulley 74 Which are interconnected through drive belt 76. Rotationof the pulleys is achieved through motor assembly MOT-1 which isrotatable in either direction to rotate the jack screw 68 to move thelens carriage 58 and lens 20 in either direction along the optical axisof the system. This movement of the lens is necessary for the opticalreductions of the system.

The optical system of the disclosed embodiment of this invention isconstructed for imaging documents at any one of five optical reductions.FIG. 1 shows the lens, in its solid line position, for imaging at anintermediate optical reduction. The dotted line positions illustrateextreme alternate position for the lens for creating other opticalreductions.

In order to receive optical reductions through a single lens, it isfurther necessary to vary the conjugate length of the optical system.This is achieved in the disclosed embodiment through the movement ofimage mirror 24. Image mirror assembly 22, as shown in FIGS. 1, 6, 7 and8 includes the image mirror 24 and mounting elements required to effectits proper movement. FIG. 1 illustrates, in the solid line position, theimage mirror oriented angle of repose with respect to the vertical toassure projection of the flowing image onto the drum at the sl1t in thelight shield. Note the dotted line showings of the varying optical axesin FIG. 1.

Image mirror 24 is mounted on a rotatable image mirror support carriage78 having externally projecting cylindrical shafts 80. Shafts 80, oneach side of the car- ;riage 78, extend into bearing apertures 82 formedin an image mirror slide block or carriage 84 for rotation of the imagemirror relative to the slide carriage. Image mirror slide carriage 84includes a pair of apertures 86 to permit the sliding motion of theslide carriage with image mirror guide rods 88 to which they are fixed.In a manner similar to the mounting of lens carriage 58, the image guiderods 88 are slidable with respect to the machine frame since oppositeends of the guide rods #88 are slidably received within bearingapertures 89 in the machine frame extensions 92.

Rotatably mounted on opposite ends of machine frame extensions 92 is arotatable image mirror jack screw 94 having a threaded surface in matingengagement with a threaded aperture 96 in the image mirror slidecarriage 84. Rotating is imparted to the jack screw 94 through drivenpulley 98 and drive pulley 100 which are interconnected through drivebelt 102. Rotating of the pulleys is achieved through motor MOT-2, whichis rotatable in either direction to rotate the jack screw 94 to move theimage mirror slide carriage 8.4 and image mirror 24 in either directionto vary the conjugate length of the As can be seen, linear motion of theimage mirror slide carriage 84 is achieved by the rotation of MOT-2 ineither direction. The required canting of the image mirror is achievedthrough follower rod 104 formed integral with one end of the supportcarriage 78. Follower rod 104 is constructed with a rotatable camfollower 106 which is urged by spring 108 into riding contact with afixed cam surface 110. Thus, as the image mirror slide carriage 84longitudinally shifts the image mirror support carriage 78 and imagemirror 24 to vary the conjugate distance of the optical system, camfollower 106 acts to vary the angular orientation of the image mirror toassure the directing of the flowing projected image through the apertureof the light shield 26 and onto the photoconductive surface 10.

By way of example, the illustrated embodiment of the instant inventionis constructed for creating copies at a 100% (1:1), 77%, 66% and 61 /2%optical reduction. The solid line showing of the lens 20 and the imagemirror 24 illustrate the optical system arranged to reproduce at 77% ofthe size of the original document on the platen 12. This is anintermediate orientation of these optical elements. When magnificationis desired, the lens is moved a predetermined distance toward the objectmirror 16 and the image mirror is moved slightly toward the objectmirror 16 and canted slightly towards the horizontal. If the greatestoptical reduction, 61 /2% is desired, the lens is moved anotherpredetermined distance away from the object mirror 16 and the imagemirror is moved away from the object mirror 16 and canted slightlytoward the vertical. It should be understood that the above notedoptical reduction could be negative reductions for creating enlargedreproductions of original documents.

The varying of the location of the lens and image mirror in the opticalsystem acts to vary the image along the axial length of the drum. Thus,if the optical system were modified as described above with no variationin the rate of scan by the oscillating object mirror 16:0r no variationin the rate of rotation of the drum, latent electrostatic images on thedrum and resultant copy therefrom would be distorted. Such distortionwould be characterized by varied optical reductions along the axiallength of the drum but 100% reproduction circumferentially on the drumdue to the fact that the scan rate and rate of rotation of the surfaceof the xerographic drum were constant. By way of example, if 100% sizereproduction of a document were desired, the object mirror would have toscan the document at the same linear speed as the surface speed of thexerographic drum. If a 50% reduction in the image of the copy of theoriginal document were desired, the scan rate of the original would haveto be twice the original rate of scan or twice the linear speed of thesurface of the xerographic drum. Therefore, since the xerographic drumis constructed to rotate at a constant surface speed, the scanning rateof the object mirror must be selectively variable with respect to theoptical reduction rate desired in order to achieve the projection of animage optically reduced in both the length and width of the image, viz,axially and longitudinally with respect to the drum.

Object mirror 16 is shown in FIGS. 1, 9, l0 and 11. It is supported onan object mirror mounting bracket 112 by springs 113 which is fixedrelative to rotatable object mirror shaft 32 for movement of the objectmirror by shaft 32 in the manner described in the aforementioned Osborneet al. patent. Mounting of the object mirror 16, mounting bracket 112,and shaft 32 are correlated so that the reflective fact of the objectmirror 16 lines on the axis of rotation of shaft 32. Motion is impartedto the oscillating object mirror 16 from motor 50 through controllersegment 40, tape 36 and the follower or controlled segment 38 in thesame manner as described in the aforementioned Osborne et al. patent. Inthe Osborne et al. patent, however, thefollower or controlled segment isfixedly keyed to the object mirror shaft for direct oscillation of theobject mirror from the oscillation of that segment. According to theinstant invention, the controlled segment 38 is rotatably journaled onthe object mirror shaft 32 for rotation relative thereto. In thismanner, a unitary oscillation of the controller and controlled segments38 and 40 may be employed to impart one of a plurality of preselectedscan rates to the object mirror shaft 32 and consequently to the objectmirror 16.

Motion of the controlled segment 38 is translated into motion of theobject mirror shaft 32 through a drive or driver gear segment 114 anddriven gear segment 116 located with their axes of rotation at a fixeddistance from each other and with their respective toothed portions inmating contact. Both of the gear segments are arranged with their mainportion in planes of rotation parallel to the plane of rotation of thecontrolled segment 38. From a speed reducing aspect, segment 38 may beconsidered the first member of the mechanism employed to effect changesin the speed of oscillation of the object mirror. The driver gearsegment 114 is formed with a cylindrical projecting arm 118 mounted inan aperture 120 in controlled segment 38. A suitable bearing assemblymay support the arm 118 and driver segment 114 for rotation with respectto the controlled segment 38. Controlled segment 38 also has anoutstanding arm 124 provided with a wheel-type cam follower 126projecting at about a right angle with respect to its toothed portion.

Driven gear segment 116 is formed with an apertured base portion securedto the object mirror shaft 32 through key 128. A neck area 130 of thedriven gear segment 116 has a cylindrical external surface upon whichthe controlled segment 38 is rotatably supported as through a suitablebearing assembly. The toothed portion of the driven gear segment is inmating engagement with the toothed portion of the driver gear segment114 with its teeth located in an arc concentric with the axis ofrotation of the object mirror shaft 32. The teeth of the driver gearsegment are located in an arc concentric with the axis of rotation ofthe rotatable projecting arm 118.

Also located in the object mirror assembly 14 is a rotatable cam base134. This cam base 134 includes a plurality of lobes 136, 138, 140, 142and 144, in a number corresponding to the number of optical reductionsof which the machine is capable. The number of lobes thus correspond tothe number of positions of the optical systems. Each lobe is providedwith a different surface cam slope designed to impart a proper motion tothe driver and driven gear segments 114 and 116 to effect a desired scanrate of the object mirror. The cam base 134 is rotatable as on asuitable bearing assembly by motor MOT-3 to bring a preselected one ofthe lobes beneath cam follower 126. Once positioned, however, the cambase 134 and consequently the preselected lobe, 136 for example, remainfixed during the oscillation of the controlled segment 38 and objectmirror 16. Oscillation of the controller segment 40 in the mannerdescribed in the aforementioned Osborne et al. patent will oscillate thecontrolled segment 38 at a Single or non-variable rate. This in turnwill impart an oscillation to the axis of projecting arm 118 which willbe a fixed rate regardless of the orientation of cam base 134 and themagnification reduction desired. The clockwise motion of the projectingarm 118 as shown in FIG. 11 will cause the entire driver gear segment114 to pivot about the axis of projecting arm 118 causing its toothedsection to rotate the driven gear segment 116 at a rate determined bythe rate of rise of cam follower 126 moving up the prepositioned lobe136 for example. Spring member 90 acts to resiliently urge the shaft 32and the driver and driven segments 114 and 116 to the start-ofscanposition. This will consequently urge cam follower 126 into continualcontact with the cam lobe 136 during scanning. Since any of the fivelobes can be selectively moved into operative relation with cam follower126, and since each lobe has a different slope corresponding to theconjugate length and position of the lens and image mirror. the rate ofrotation of the driven gear segment 116 and rate of scan of objectmirror 16 can be regulated to correspond with the optical reductiondesired.

The lobe segments are designed so that the points thereon representingtheir points of contact with the cam follower at any start-of-scanposition are equidistant from the axis of rotation of shaft 32. In thismanner the object scanning mirror 16 has the same start-of-scanorientation for any lobe segment employed or any rate of scan desired.

Shown in FIG. 1 is a machine console 148 substantially the same as thatdisclosed in the aforementioned Osborne et al. patent, the functioningbuttons and indicator lights operating in the same fashion as disclosedtherein. In addition thereto, there is also provided a plurality ofoptical reduction selector buttons generally indicated as 150. If, forexample, the machine is put in operation by depressing the POWER ONbutton and START PRINT, the light behind the optical reduction selectorbutton would be illuminated to indicate the last used optical reductionstate of the machine. The machine would then be conditioned to createcopies at the preselected optical reduction rate. If, however, adifferent rate were desired, the button indicating the new rate would bedepressed by the operator. If desired, the controls could be programmedto return the machine to the (1:1) imaging rate each time a run ofreduced size images were made.

The depression of a new optical reduction rate button acts to initiatethe programmed operation of MOT l, MOT-2 and MOT-3, respectively. Theprogrammed indexing and stopping of the motors and their associatedmechanisms may be accomplished by conventional programming techniques,for example, those disclosed for indexing and stopping the motors andmechanisms in the machine described in US. Pat. No. 3,355,236, to G. P.Taillie et al. The programmed operation of MOT1 will move the lenscarriage 58 and lense 20 along the optical axis of the system to alocation corresponding to the selected optical reduction rate. Theprogrammed operation of MOT2 will also move the image mirror slidecarriage 84 in a longitudinal path to its proper orientation with camfollower 106 riding on cam surface to produce the proper angle of imagemirror 24 to allow the projecting of the image onto the xerographicdrum. In like fashion, MOT-3 is actuated in a programmed fashion tobring the appropriate lobe on cam base 134 beneath cam follower 126 sothat the rate of scan of the image by object mirror 16 can be correlatedto the orientation of lens 20 and image mirror 24. The correlation ofthese elements, including the rate of scan, produces preselected opticalreduction rates with no distortion in the copy.

As will be understood, the optical reduction rates shown herein, are byway of example only. The lobe sections 136, 138, etc., may be maderemovable from cam base 134 so that other optical reduction rates may beachieved as desired. Cam base 134 may also be designed to accommodateany number of lobes of varying slope. In association therewith, themotors MOT-1, MOT-2 and MOT-3 would be programmed to correspond to thepredesigned slope of the lobes.

While the present invention, as to its objects and advantages, has beendescribed as carried out in a specific embodiment thereof, it is notdesired to be limited thereby; but it is intended to cover the inventionbroadly within the scope of the appended claims.

What is claimed is:

1. A mechanism for converting a constant velocity, constant throwmovement of a first member into a rotational oscillation of a secondmember comprising, in combination,

a first member rotatable about a first axis of rotation,

a drive segment mounted on said first member for rotation about a secondaxis of rotation offset from said first axis of rotation,

a driven segment mounted for rotation about said first axis of rotation,

means operatively interconnecting said drive segment and said drivensegment so that movement of said drive segment results in a correlatedmovement of said driven segment,

a'cam follower on said drive segment, said cam follower being offsetfrom said v first axis and said second axis,

a cam surface positionable in contact with said cam follower so thatrotational movement of said first member will move the axis of rotationof said drive segment as well as rotate the drive segment about its axisof rotation due to the movement of said cam follower along said camsurface so "that the movement of said drive" segment and said drivensegment is a function of the rotational speed of said first member andthe characteristics of said cam surface and a plurality of supplementalcam surfaces selectively positionable into contact with said camfollower, each of said cam surfaces being of a different slope so thatthe speed of rotation of said driven segment is a function of the camsurface positioned in contact with said cam follower.

2. The mechanism as set forth in claim 1 wherein said means operativelyinterconnecting said drive segment and said driven segment includesintermeshing gear teeth on said drive segment and said driven segment.

3. The mechanism as set forth in claim -1 and further including meansresiliently, urging said driven segment in a direction to oppose itsrotation by said drive segment.

4. The mechanism as set forth in claim 1 wherein each of said camsurfaces has an initial portion equidistant from said first axis ofrotation to permit the start of rotation point of said driven segment tobe the same for any of the cam surfaces employed.

5. The mechanism as set forth in claim 1 and further including meanstforsupporting all of said cam surfaces constant throw movement of a firstmember into a rotational oscillation of a second member comprising, incombination.

a first member oscillatory about a first axis of rotation,

a drive segment mounted on said first member for rotation about a secondaxis of rotation offset from said first axis of rotation,

means operatively interconnecting said drive segment and said drivensegment so that movement of said i drive segment results in a correlatedmovement of said driven segment,

a cam follower on said drive segment, said cam follower being offsetfrom said first axis and said second axis, and

a cam surface positionable in contact with said cam follower so thatoscillatory movement of said first member will oscillate the axisjofrotation of said drive segment as well as rotate the drive segment aboutits axis of rotation due to the movement of said cam follower along saidcam surface so that the movement of said drive segment and said drivensegment is a function of the rotational speed of said first member andthe characteristics of said cam surface.

References Cited UNITED STATES PATENTS 2,566,945 9/1951 Laze 74-4352,917,939- 12/1959 Harris 74 -435 3,026,732 3/1962 Corvisier 741423,301,126 l/1967 Osborne et a1. 3558 WESLEY S. RATLIFF, JR., PrimaryExaminer

